Intestines-histo

Question 1

what is the function of the SI

Answer 1

absorption

Question 2

What are the 3 magnitudes of folding of the SI

Answer 2

microvilli, villi and plicacirculares

Question 3

describe microvilli

Answer 3

cytoplasmic projections of cell membrane- simple columnar epitheliums

Question 4

What is the structure of villi

Answer 4

evaginations of mucosa with a core of lamina propria that project into the lumen

Question 5

what do villi look like in the 3 parts of SI

Answer 5

duodenum- broad short and leaf like
jejunum- tongue like projections
in ileum- tall, narrow, finger-like projections

Question 6

what is the structure of plicae circulares

Answer 6

circular folds of entire mucosa with a core of submucosa

permanent projections into lumen

Question 7

where are plicae circulares most prominent

Answer 7

distal duodenum and proximal jejunum

Question 8

what are the 3 categories of glands in SI

Answer 8

exocrine, submucosal and intestinal crypts

Question 9

what are the exocrine glands of the SI

Answer 9

pancreas and liver

Question 10

what are the submucosal glands of the SI

Answer 10

duodenal

Question 11

Whar are the intestinal crypts of the SI

Answer 11

epithelium invaginating into lamina propria in small and large intestine

Question 12

Whar type of epithelium is the SI

Answer 12

simple columnar epithelium replaced every 3-7 days

Question 13

what cells are present in SI epithelium

Answer 13

absorptive columnar with microvilli
goblet cells
lymphocytes
enteroendocrine cells
paneth cells
M cells

Question 14

What are enteroendocrine cells

Answer 14

secrete product into vascular channels in lamina propria

Question 15

What products do enteroendocrine cells secrete

Answer 15

incretins (K cells)
GIP (L cells)
serotonin (enterochromaffin cells)
somatostatin
motilin
cholecystokinin
neurotensin
VIP
substance P
endorphins

Question 16

where are paneth cells found

Answer 16

in the base of intestinal crypts

Question 17

describe characterizations of paneth cells

Answer 17

large acidophilic granules

Question 18

what do paneth cells secrete

Answer 18

lysozyme and peptide defensins

Question 19

what is the role of lysozymes and peptide defensins

Answer 19

degrade bacterial cell wall components

Question 20

What are M cells and what is their role

Answer 20

specialized cells in epithelium that are part of innate and classic immune system because the actively capture and transport Ag to APCs and B cells in lamina propria

Question 21

describe the lamina propria structure and function of AI

Answer 21

loose CT prone to lymphoid infiltration so have lots of plasma cells that can produce IgA
also have lots of capillaries”lacteals” that begin blindly in the villi
have lymph nodules called peyers patches

Question 22

where are peyers patches most prominent in SI

Answer 22

ileum and maybe lower jejunum

Question 23

Where are M cells most prevalent in SI

Answer 23

ileum and l=maybe lower jejunum

Question 24

Describe the layers of the SI wall

Answer 24

submucosa with lymphocytes and peyers patches
muscularis externa
serosa

Question 25

describe the serosa of the 3 parts of SI

Answer 25

duodenum has serosa anteriorly because retroperitoneal | ileum and jéjunum have serosa continuous with supporting mesentery

Question 26

What is the ileocecal junction

Answer 26

ileum joins large intestine

Question 27

what structures make up the ileocecal junction

Answer 27

folds of mucosa and submucosa supported by muscularis externa

Question 28

the cecum is structurally identical to what part of gut

Answer 28

large intestine- colon

Question 29

What type of cells are found in the appendix

Answer 29

intestinal crypts of enteroendocrine cells and paneth cells

Question 30

describe the epithelium of appendix

Answer 30

simple columnar epithelium with goblet cells

Question 31

describe layers of appendix wall

Answer 31

muscularis mucosa is incomplete submucosa is thick thin 2 layered muscularis externa typical serosa

Question 32

Are there villi on the large intestine

Answer 32

no

Question 33

What are the intestinal crypts called in large intestine

Answer 33

crypts of lieberkuhn

Question 34

describe the intestinal crypts of the large intestine

Answer 34

longer and more closely packed than in SI | have some enteroendocrine cells and no paneth cells

Question 35

What is the surface epithelium like in the large intestine

Answer 35

simple columnar but many many goblet cells and no digestive enzymes are secreted

Question 36

why are there numerous goblet cell sin large intestine compared to small

Answer 36

fecal matter is solidified now and needs lubrication

Question 37

instead of plica circulates, what is in the large intestine

Answer 37

plica semilunares that form haustra

Question 38

describe the muscularis externa layer of the large intestine

Answer 38

inner layer completely encircles submucosa | outer longitudinal layer in 3 longitudinal bands

Question 39

what is the name of the 3 longitudinal bands of the outer layer of muscularis externa

Answer 39

taeniae coli

Question 40

describe the serosa of the large intestine

Answer 40

on anterior surface but not posterior

Question 41

what is the name of the small sacs of fat on the large intestine

Answer 41

epiploic appendages

Question 42

describe the muscularis externa of the rectum

Answer 42

complete and there are no taeniae coli anymore because form outer m layer

Question 43

describe serosa of rectum

Answer 43

upper 1/3 is intraperitoneal and has serosa anterior surface in middle 1/3 has serosa becase retroperitoneal lower 1/3 does not have serosa because extraperitoneal now

Question 44

What are the plicae transversales of the rectum

Answer 44

transverse folds of mucosa that bulge into lumen 2 on left 1 on right

Question 45

where is the rectoanal junction

Answer 45

where rectum pierces perineum

Question 46

Describe the changes at the rectoanal junction

Answer 46

intestinal crypts decrease in number till they disappear and the mucous membrane forms longitudinal folds known as rectal columns

Question 47

how does epithelium change across pectinate line

Answer 47

simple columnar becomes stratified squamous non cornfield and becomes continuous with the skin

Question 48

describe the submucosal Ct of the anal canal

Answer 48

subepithelial circumanal glands longitudinal thin walled vv (hemorrhoidal vv)

Question 49

Describe the muscularis externa of the anal canal

Answer 49

internal layer thickens to form internal anal sphincter | external sphincter is formed by skel m

Question 50

Where is the anal verge

Answer 50

caudal portion of anal canal

Question 51

what is the epithelium like at the anal verge

Answer 51

stratified squamous keratinized with sweat glands, hair follicles, sebaceous glands